Statins are one of the most commonly prescribed medications in the United States with almost half of the older adult population aged >75 years prescribed statins for primary or secondary prevention of cardiovascular disease (CVD) from 2012 to 2013. The high prevalence of statin prescribing is alarming given the lack of evidence to support its use among those of advanced age. The 2016 US Preventative Services Task Force declared insufficient evidence to recommend for or against statin use for primary prevention of CVD in those aged ?75 years and did not address statin use for secondary prevention. Statin-related adverse events can be serious and may increase in prevalence and severity among older clinically complex populations. The US Drug and Food Administration (FDA) recognizes these concerns, but provider warnings are not age-specific. A recent clinical trial showed that discontinuing statin therapy among older adults with limited life expectancy is not only safe, but also improves quality of life, while decreasing overall costs. Given that 40% of the nursing home population are aged >85 years and that a large proportion of this population have life-limiting illnesses or progressive incurable conditions with limited life expectancies, nursing homes residents may be particularly prone to overuse of statins. There are currently no studies that have evaluated statin use across a national sample of US nursing homes. This R36 dissertation proposal seeks to address this gap in the literature, specifically designed to evaluate trends and safety of statin use among long-stay nursing homes residents ? a vulnerable population not likely to benefit from continued use of statins, but who are at increased risk of statin adverse effects. This proposal leverages a rich, in-house, contemporary data source of virtually all nursing home residents in the US (2011-2016). The Minimum Data Set (MDS 3.0), a repository of all resident health assessments, has been merged to Medicare Part A claims, Medicare Part D claims, and facility-level data included as part of Certification and Survey Provider and Enhanced Reporting (CASPER). The comprehensive, longitudinal MDS assessments include validated instruments (e.g., cognitive, physical impairments), socio-demographic, and clinical variables. Advanced statistical techniques proposed include longitudinal and multilevel analyses to reduce confounding, bias, and model misspecification. The specific aims are to: 1) Describe trends of statin utilization (including type of agents and dosage) of nursing home residents overall, by long- and skilled nursing facility stays, and by life-limiting illnesses; 2) Identify sociodemographic, clinical, and facility level associations with statin use among nursing home residents with life-limiting illness; 3) Among statin users, estimate the extent to which statins are discontinued during the nursing home stay and evaluate resident- and facility- level factors associated with time to statin discontinuation; 4) Compare the incidence of 1-year safety (i.e., mortality) and effectiveness (i.e., CVD hospitalization) outcomes between residents continuing vs. discontinuing statins. The proposed research will generate foundational knowledge on an important clinical topic in an often forgotten vulnerable population.